Monitoring of the environmental parameters of the sea is important for various meteorological, oceanographic, and fishing activities. For example, successful tracking and harvesting of lobsters requires knowledge of temperatures, salinity, and other parameters as a function of depth, and mapping of these parameters can provide valuable predictive information for fishermen. There are known technologies to remotely monitor and report temperature in the open sea. For example, fixed buoys can be anchored in certain positions in the sea and continuously measure and report temperature at a certain depth corresponding to the immersion depth of the temperature monitoring device attached to the a fixed buoy. On the other hand, drifting buoys can be released in a body of water and move with the currents over a period of days, weeks, or months, with on-board electronics typically transmitting a radio signal that is detected by a satellite network, giving sensor data and location of the buoy.
These known techniques only enable measurement of the temperature at a fixed depth. In order to measure temperature at different depths and over range of time, a manual measurement typically involving an operator and ship present at the location are needed, whereby a temperature sensing device is immersed in the ocean and measurements are performed as a function of the immersion depth. This procedure is expensive, time consuming, and not practical.
Dataloggers incorporating devices/sensors that are capable of measuring salinity, temperature, depth (pressure), and conductivity, and are designed as archival tags for analyzing fish migration, distribution, and feeding behavior, are also known in the art. The dataloggers can be attached to fish as tags or used as stand-alone monitors for sampling in the ocean. They can be also fastened to fishing gear as temperature and pressure monitors. The disadvantage of these devices is difficulty of retrieving and timely reporting the information collected by fish-attached tags or by stand-alone monitors. As a result the information is not being collected at a scale it is needed, and there are significant delays in analyzing the information and providing such information to fishing industry. Wireless transmission of data from undersea autonomous dataloggers is impossible due to high depth and consequent attenuation of the signal. The transmission of the data is only practical once an autonomous probe or a datalogger is on the sea surface. However activating the transmission requires extensive device handling, such as retrieval of the device, cleaning, connection to data collection ports, etc., which may require a dedicated operator which is impractical on a ship. Some currently known sea-bottom sensors must be disconnected from fishing gear or trap, cleaned to expose the infra-red (IR) port, inserted into a reader connected to a PC and then reattached to the fishing gear or trap. Depth and position must be recorded separately and can confound the temperature data if records are inaccurate or incomplete. These procedures, when performed on a fishing vessel by working fishermen and on multiple probes, are complicated and not practical.
Devices that attempt to continuously wirelessly transmit the data will suffer from very quick depletion of the undersea probe power supply and hence require either battery replacement, re-charge, or installation of a new probe, which is expensive and impractical. As a result, the data collected using existing devices is uploaded only infrequently and is not available in real time.
There is a need for fully automated collection and reporting of undersea environmental parameters as a function of depth, time, and location using low cost, easy to use, autonomously powered devices.